From all I have read you cannot do exactly what you want without javascript. If you float left before text
<div style="float:left;">widget</div> here is some CONTENT, etc.
Your content wraps as expected. But your widget is in the top left. If you instead put the float after the content
here is some CONTENT, etc. <div style="float:left;">widget</div>
Then your content will wrap the last line to the right of the widget if the last line of content can fit to the right of the widget, otherwise no wrapping is done. To make borders and backgrounds actually include the floated area in the previous example, most people add:
here is some CONTENT, etc. <div style="float:left;">widget</div><div style="clear:both;"></div>
In your question you are using bootstrap which just adds row-fluid::after { content: ""} which resolves the border/background issue.
Moving your content up will give you the one line wrap : http://jsfiddle.net/jJNPY/34/
<div class="container-fluid">
<div class="row-fluid">
<div class="offset1 span8 pull-right">
... Widget 1...
</div>
.... a lot of content ....
<div class="span8" style="margin-left: 0;">
... Widget 2...
</div>
</div>
</div><!--/.fluid-container-->